#
def binary_search(dataset, start, stop, data):
    if start > stop:
        raise Exception("Can not find data")

    m = (start + stop) // 2
    if dataset[m] == data:
        return data
    elif data < dataset[m]:
        return binary_search(dataset, start, m - 1, data)
    else:
        return binary_search(dataset, m + 1, stop, data)



print(binary_search([1], 0, 0, 1))